Transient Photon Beams

We present a method for efficient transient rendering of participating media based on the time-resolved radiative transfer equation and photon beams techniques. In the left image we can observe a classic steady-state render of a glass armadillo within a participating media. On the right we show the frame sequence of the time-resolved response under a delta pulse of light. We leverage density estimation properties of photon-based methods for mitigating aggravated variance of Monte Carlo sampling in the light temporal domain. Our method allows to efficiently render complex media effects such as caustics and multiple scattering in transient state.

Abstract

Recent advances on transient imaging and their applications have opened the necessity of forward models that allow precise generation and analysis of time-resolved light transport data. However, traditional steady-state rendering techniques are not suitable for computing transient light transport due to the aggravation of the inherent Monte Carlo variance over time. These issues are specially problematic in participating media, which demand high number of samples to achieve noise-free solutions. We address this problem by presenting the first photon-based method for transient rendering of participating media that performs density estimations on time-resolved precomputed photon maps. We first introduce the transient integral form of the radiative transfer equation into the computer graphics community, including transient delays on the scattering events. Based on this formulation we leverage the high density and parameterized continuity provided by photon beams algorithms to present a new transient method that allows to significantly mitigate variance and efficiently render participating media effects in transient state.

Cite

@inproceedings{marco17transient,
author = "Marco, Julio and Jarosz, Wojciech and Gutierrez, Diego and Jarabo, Adrian",
booktitle = "Spanish Computer Graphics Conference (CEIG)",
title = "Transient Photon Beams",
month = "jun",
year = "2017",
publisher = "The Eurographics Association",
isbn = "978-3-03868-046-8",
doi = "10.2312/ceig.20171216",
abstract = "Recent advances on transient imaging and their applications have opened the necessity of forward models that allow precise generation and analysis of time-resolved light transport data. However, traditional steady-state rendering techniques are not suitable for computing transient light transport due to the aggravation of the inherent Monte Carlo variance over time. These issues are specially problematic in participating media, which demand high number of samples to achieve noise-free solutions. We address this problem by presenting the first photon-based method for transient rendering of participating media that performs density estimations on time-resolved precomputed photon maps. We first introduce the transient integral form of the radiative transfer equation into the computer graphics community, including transient delays on the scattering events. Based on this formulation we leverage the high density and parameterized continuity provided by photon beams algorithms to present a new transient method that allows to significantly mitigate variance and efficiently render participating media effects in transient state."
}